mesa: Add validation helpers for new indirect draws

Based on part of Patch 2 of Christoph Bumiller's ARB_draw_indirect series.

V3: - Disallow primcount==0 for DrawMulti*Indirect. The spec is unclear
      on this, but it's silly. We might go back on this later if it
      turns out to be a problem.

    - Make it clear that the caller has dealt with stride==0

V4: - Allow primcount==0 again.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/mesa/main/api_validate.c

@@ -837,3 +837,195 @@ _mesa_validate_DrawTransformFeedback(struct gl_context *ctx,
 
    return GL_TRUE;
 }
+
+static GLboolean
+valid_draw_indirect(struct gl_context *ctx,
+                    GLenum mode, const GLvoid *indirect,
+                    GLsizei size, const char *name)
+{
+   const GLsizeiptr end = (GLsizeiptr)indirect + size;
+
+   if (!_mesa_valid_prim_mode(ctx, mode, name))
+      return GL_FALSE;
+
+
+   /* From the ARB_draw_indirect specification:
+    * "An INVALID_OPERATION error is generated [...] if <indirect> is no
+    *  word aligned."
+    */
+   if ((GLsizeiptr)indirect & (sizeof(GLuint) - 1)) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "%s(indirect is not aligned)", name);
+      return GL_FALSE;
+   }
+
+   if (!_mesa_is_bufferobj(ctx->DrawIndirectBuffer)) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "%s: no buffer bound to DRAW_INDIRECT_BUFFER", name);
+      return GL_FALSE;
+   }
+
+   if (_mesa_bufferobj_mapped(ctx->DrawIndirectBuffer)) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "%s(DRAW_INDIRECT_BUFFER is mapped)", name);
+      return GL_FALSE;
+   }
+
+   /* From the ARB_draw_indirect specification:
+    * "An INVALID_OPERATION error is generated if the commands source data
+    *  beyond the end of the buffer object [...]"
+    */
+   if (ctx->DrawIndirectBuffer->Size < end) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "%s(DRAW_INDIRECT_BUFFER too small)", name);
+      return GL_FALSE;
+   }
+
+   if (!check_valid_to_render(ctx, name))
+      return GL_FALSE;
+
+   return GL_TRUE;
+}
+
+static inline GLboolean
+valid_draw_indirect_elements(struct gl_context *ctx,
+                             GLenum mode, GLenum type, const GLvoid *indirect,
+                             GLsizeiptr size, const char *name)
+{
+   if (!valid_elements_type(ctx, type, name))
+      return GL_FALSE;
+
+   /*
+    * Unlike regular DrawElementsInstancedBaseVertex commands, the indices
+    * may not come from a client array and must come from an index buffer.
+    * If no element array buffer is bound, an INVALID_OPERATION error is
+    * generated.
+    */
+   if (!_mesa_is_bufferobj(ctx->Array.ArrayObj->ElementArrayBufferObj)) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "%s(no buffer bound to GL_ELEMENT_ARRAY_BUFFER)", name);
+      return GL_FALSE;
+   }
+
+   return valid_draw_indirect(ctx, mode, indirect, size, name);
+}
+
+static inline GLboolean
+valid_draw_indirect_multi(struct gl_context *ctx,
+                          GLsizei primcount, GLsizei stride,
+                          const char *name)
+{
+
+   /* From the ARB_multi_draw_indirect specification:
+    * "INVALID_VALUE is generated by MultiDrawArraysIndirect or
+    *  MultiDrawElementsIndirect if <primcount> is negative."
+    *
+    * "<primcount> must be positive, otherwise an INVALID_VALUE error will
+    *  be generated."
+    */
+   if (primcount < 0) {
+      _mesa_error(ctx, GL_INVALID_VALUE, "%s(primcount < 0)", name);
+      return GL_FALSE;
+   }
+
+
+   /* From the ARB_multi_draw_indirect specification:
+    * "<stride> must be a multiple of four, otherwise an INVALID_VALUE
+    *  error is generated."
+    */
+   if (stride % 4) {
+      _mesa_error(ctx, GL_INVALID_VALUE, "%s(stride %% 4)", name);
+      return GL_FALSE;
+   }
+
+   return GL_TRUE;
+}
+
+GLboolean
+_mesa_validate_DrawArraysIndirect(struct gl_context *ctx,
+                                  GLenum mode,
+                                  const GLvoid *indirect)
+{
+   const unsigned drawArraysNumParams = 4;
+
+   FLUSH_CURRENT(ctx, 0);
+
+   return valid_draw_indirect(ctx, mode,
+                              indirect, drawArraysNumParams * sizeof(GLuint),
+                              "glDrawArraysIndirect");
+}
+
+GLboolean
+_mesa_validate_DrawElementsIndirect(struct gl_context *ctx,
+                                    GLenum mode, GLenum type,
+                                    const GLvoid *indirect)
+{
+   const unsigned drawElementsNumParams = 5;
+
+   FLUSH_CURRENT(ctx, 0);
+
+   return valid_draw_indirect_elements(ctx, mode, type,
+                                       indirect, drawElementsNumParams * sizeof(GLuint),
+                                       "glDrawElementsIndirect");
+}
+
+GLboolean
+_mesa_validate_MultiDrawArraysIndirect(struct gl_context *ctx,
+                                       GLenum mode,
+                                       const GLvoid *indirect,
+                                       GLsizei primcount, GLsizei stride)
+{
+   GLsizeiptr size = 0;
+   const unsigned drawArraysNumParams = 4;
+
+   FLUSH_CURRENT(ctx, 0);
+
+   /* caller has converted stride==0 to drawArraysNumParams * sizeof(GLuint) */
+   assert(stride != 0);
+
+   if (!valid_draw_indirect_multi(ctx, primcount, stride,
+                                  "glMultiDrawArraysIndirect"))
+      return GL_FALSE;
+
+   /* number of bytes of the indirect buffer which will be read */
+   size = primcount
+      ? (primcount - 1) * stride + drawArraysNumParams * sizeof(GLuint)
+      : 0;
+
+   if (!valid_draw_indirect(ctx, mode, indirect, size,
+                            "glMultiDrawArraysIndirect"))
+      return GL_FALSE;
+
+   return GL_TRUE;
+}
+
+GLboolean
+_mesa_validate_MultiDrawElementsIndirect(struct gl_context *ctx,
+                                         GLenum mode, GLenum type,
+                                         const GLvoid *indirect,
+                                         GLsizei primcount, GLsizei stride)
+{
+   GLsizeiptr size = 0;
+   const unsigned drawElementsNumParams = 5;
+
+   FLUSH_CURRENT(ctx, 0);
+
+   /* caller has converted stride==0 to drawElementsNumParams * sizeof(GLuint) */
+   assert(stride != 0);
+
+   if (!valid_draw_indirect_multi(ctx, primcount, stride,
+                                  "glMultiDrawElementsIndirect"))
+      return GL_FALSE;
+
+   /* number of bytes of the indirect buffer which will be read */
+   size = primcount
+      ? (primcount - 1) * stride + drawElementsNumParams * sizeof(GLuint)
+      : 0;
+
+   if (!valid_draw_indirect_elements(ctx, mode, type,
+                                     indirect, size,
+                                     "glMultiDrawElementsIndirect"))
+      return GL_FALSE;
+
+   return GL_TRUE;
+}

src/mesa/main/api_validate.h

@@ -87,5 +87,31 @@ _mesa_validate_DrawTransformFeedback(struct gl_context *ctx,
                                      GLuint stream,
                                      GLsizei numInstances);
 
+extern GLboolean
+_mesa_validate_DrawArraysIndirect(struct gl_context *ctx,
+                                  GLenum mode,
+                                  const GLvoid *indirect);
+
+extern GLboolean
+_mesa_validate_DrawElementsIndirect(struct gl_context *ctx,
+                                    GLenum mode,
+                                    GLenum type,
+                                    const GLvoid *indirect);
+
+extern GLboolean
+_mesa_validate_MultiDrawArraysIndirect(struct gl_context *ctx,
+                                       GLenum mode,
+                                       const GLvoid *indirect,
+                                       GLsizei primcount,
+                                       GLsizei stride);
+
+extern GLboolean
+_mesa_validate_MultiDrawElementsIndirect(struct gl_context *ctx,
+                                         GLenum mode,
+                                         GLenum type,
+                                         const GLvoid *indirect,
+                                         GLsizei primcount,
+                                         GLsizei stride);
+
 
 #endif